CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common and Class B Common Stock ($1 par value) (Note 12)	Additional paid-in capital	Accumulated other comprehensive income (loss)	Retained Earnings	Treasury stock	Noncontrolling interests
Beginning balance at Dec. 31, 2014	$ 700,453	$ 24,358	$ 179,205	$ 12,555	$ 479,733	$ (2,666)	$ 7,268
Increase (Decrease) in Stockholders' Equity
Net income (loss) attributable to Stewart	(6,204)				(6,204)
Dividends on Common Stock	(18,010)				(18,010)
Stock bonuses and other (including tax effects)	4,851	93	4,758
Exercise of stock options	130	4	126
Stock repurchases	(27,950)	(762)	(27,188)
Purchase of remaining interest of consolidated subsidiary	(209)		(209)
Net change in unrealized gains and losses on investments (net of tax)	(3,741)			(3,741)
Net realized gain reclassification (net of tax)	(1,626)			(1,626)
Foreign currency translation (net of tax)	(11,145)			(11,145)
Net income attributable to noncontrolling interests	10,247						10,247
Distributions to noncontrolling interests	(9,706)						(9,706)
Net effect of changes in ownership and other	38						38
Ending balance at Dec. 31, 2015	637,128	23,693	156,692	(3,957)	455,519	(2,666)	7,847
Increase (Decrease) in Stockholders' Equity
Cumulative effect adjustment on adoption of ASU 2016-09 (Note 12)	0		(631)		631
Net income (loss) attributable to Stewart	55,478				55,478
Dividends on Common Stock	(27,840)				(27,840)
Cash paid on Class B Common Shares conversion	(12,000)				(12,000)
Stock bonuses and other (including tax effects)	2,982	110	2,872
Exercise of stock options	86	3	83
Stock repurchases	(1,053)	(23)	(1,030)
Purchase of remaining interest of consolidated subsidiary	(991)		(810)				(181)
Net change in unrealized gains and losses on investments (net of tax)	354			354
Net realized gain reclassification (net of tax)	(1,911)			(1,911)
Foreign currency translation (net of tax)	(3,367)			(3,367)
Net income attributable to noncontrolling interests	12,943						12,943
Distributions to noncontrolling interests	(12,961)						(12,961)
Ending balance at Dec. 31, 2016	648,848	23,783	157,176	(8,881)	471,788	(2,666)	7,648
Increase (Decrease) in Stockholders' Equity
Net income (loss) attributable to Stewart	48,659				48,659
Dividends on Common Stock	(28,749)				(28,749)
Stock bonuses and other (including tax effects)	5,303	306	4,997
Stock repurchases	(727)	(17)	(710)
Purchase of remaining interest of consolidated subsidiary	(1,810)		(1,509)				(301)
Net change in unrealized gains and losses on investments (net of tax)	1,766			1,766
Net realized gain reclassification (net of tax)	(2,086)			(2,086)
Foreign currency translation (net of tax)	8,354			8,354
Net income attributable to noncontrolling interests	11,487						11,487
Distributions to noncontrolling interests	(11,651)						(11,651)
Net effect of changes in ownership and other	(584)						(584)
Ending balance at Dec. 31, 2017	$ 678,810	$ 24,072	$ 159,954	$ (847)	$ 491,698	$ (2,666)	$ 6,599